Whether Andrew Sendejo is fighting for a roster spot or earning millions in the preseason, his approach doesn't differ.

The 28-year-old Vikings safety appears to have locked up the starting job next to Harrison Smith, solidifying his case in Sunday's 23-10 exhibition victory over the San Diego Chargers. Sendejo played the entire game because injuries thinned his teammates — and competition — which forced coach Mike Zimmer to stick with his front-runner throughout the exhibition.

When both the Vikings and Chargers were reaching deep down their preseason rosters, Sendejo was barreling through linemen on a fourth-down stop and undercutting another blocker for another fourth-quarter loss of yards.

"That's definitely what I know we're getting out of Sendejo," Smith said. "A guy who is going to stick people and make plays."

On a four-year, $16 million contract newly signed this offseason, Sendejo could have tiptoed through the rest of a game in which the outcome was meaningless. That wouldn't have been his style. A "play like you never know" mentality was forged by an NFL career that started as an undrafted free agent in 2010 and included a detour in the now-disbanded United Football League.

"I'm used to it. Ever since I've been in the league, I've played all preseason games and everything," Sendejo said. "In this league, it can be vicious. You're never just safe. You always have to grind like you're on the bubble."

After 13 starts last season, Sendejo's job still wasn't secured. Zimmer openly questioned if he had the "right kind" of safety to pair with Smith, who himself earned a five-year, $51.25 million extension in June. The Vikings ponied up $4 million guaranteed to keep Sendejo, using a one-year deal to bring in his primary competition in veteran Michael Griffin.

Griffin, who played through two finger dislocations in the preseason opener at Cincinnati, made one start next to Smith, in the second game at Seattle. He came off the bench Sunday, when his audition was cut short due to a back injury suffered shortly after he missed Chargers running back Melvin Gordon on a 39-yard touchdown run. That was after third-year safety Antone Exum Jr. was forced out because of a leg injury.

Asked if he gained clarity in the safety competition, Zimmer said he would rather tell his players first.

"I think I have an idea," Zimmer said. "I know you guys have to ask me, but it's important I tell the players where I think they are before I tell you guys."

Code red

An undefeated record in the preseason provides comfort to only boxscore checkers.

After praising quarterback Teddy Bridgewater's day, Zimmer provided a candid review of the Vikings red zone offense, which failed on the opening two possessions to cross the goal line with first downs from the Chargers' 6- and 7-yard line. Blair Walsh made two field goals, from 23 and 33 yards, to give them a 6-0 lead.

"Well, it's not very good right now," Zimmer said. "We need to get better at it, for sure. I thought we did a great job getting down there, but we gotta come away with touchdowns."

Last year, the Vikings ranked 25th in the NFL in touchdowns per red-zone drive (. 500), according to Football Outsiders.

Injury update

Tight end MyCole Pruitt and Exum are set to undergo magnetic resonance imaging scans on Monday.

Both were forced to leave Sunday's game early due to leg injuries. Exum had a brace on his left knee after the game. Pruitt didn't return after an 11-yard catch and fumble.

Griffin (back) was seen leaving the locker room on crutches.

Left tackle Matt Kalil (leg), cornerback Xavier Rhodes (hamstring), tight end Rhett Ellison (knee), defensive tackle Scott Crichton and safety Anthony Harris did not play.